Triplet-triplet energy transfer from chlorophylls to carotenoids in two antenna complexes from dinoflagellate Amphidinium carterae

0460501 - BC 2017 RIV NL eng J - Journal Article
Kvíčalová, Z. - Alster, J. - Hofmann, E. - Khoroshyy, P. - Litvín, Radek - Bína, David - Polívka, Tomáš - Pšenčík, J.
Triplet-triplet energy transfer from chlorophylls to carotenoids in two antenna complexes from dinoflagellate Amphidinium carterae.
Biochimica Et Biophysica Acta-Bioenergetics. Roč. 1857, č. 4 (2016), s. 341-349. ISSN 0005-2728. E-ISSN 1879-2650
R&D Projects: GA ČR GBP501/12/G055
Institutional support: RVO:60077344
Keywords : Dinoflagellate * Chlorophyll * Carotenoid * Triplet state
Subject RIV: BO - Biophysics
Impact factor: 4.932, year: 2016

Room temperature transient absorption spectroscopy with nanosecond resolution was used to study quenching of the chlorophyll triplet states by carotenoids in two light-harvesting complexes of the dinoflagellate Amphidinium carterae: the water soluble peridinin-chlorophyll protein complex and intrinsic, membrane chlorophyll a-chlorophyll c(2)-peridinin protein complex. The combined study of the two complexes facilitated interpretation of a rather complicated relaxation observed in the intrinsic complex. While a single carotenoid triplet state was resolved in the peridinin-chlorophyll protein complex, evidence of at least two different carotenoid triplets was obtained for the intrinsic light-harvesting complex. Most probably, each of these carotenoids protects different chlorophylls. In both complexes the quenching of the chlorophyll triplet states by carotenoids occurs with a very high efficiency (similar to 100%), and with transfer times estimated to be in the order of 0.1 ns or even faster. The triplet-triplet energy transfer is thus much faster than formation of the chlorophyll triplet states by intersystem crossing. Since the triplet states of chlorophylls are formed during the whole lifetime of their singlet states, the apparent lifetimes of both states are the same, and observed to be equal to the carotenoid triplet state rise time (similar to 5 ns). (C) 2016 Elsevier B.V. All rights reserved.
Permanent Link: http://hdl.handle.net/11104/0260560